Phendimetrazine
BONTRIL
Pronunciation: fen-dye-MET-ra-zeen
What it isNorepinephrine-releasing sympathomimetic and prodrug of phenmetrazine; brief adjunct for weight management.
Why this oneConversion to phenmetrazine brings substantial stimulant and abuse liability with little role beyond short-term appetite suppression.
What limits itBlood pressure and heart rate rise; avoid cardiovascular disease and MAOIs. Tolerance and dependence limit use.
Phendimetrazine prescription history
Animated chart of estimated U.S. prescriptions per year, Obesity meds (1959–2026). Phendimetrazine enters in 1959 (estimated).
Principal riskBlood pressure and heart rate rise; short-term use only
Classes and tags
Clinical profile
Defining liabilityDependence and cardiovascular stimulation
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Exogenous obesity, short-term adjunct (a few weeks) to caloric restriction; BMI ≥30, or ≥27 with risk factors; monotherapy only | Adults | 105 mg (1 ER cap) QAM, 30–60 min before breakfast | 105 mg QAM | 105 mg QD (1 capsule) |
Renal Not studied; renally excreted — exposure increase expected, use caution
Hepatic Undefined
Not recommended <17 years (pediatric safety not established)
Instructions
- Take in the morning, 30 to 60 minutes before morning meal
- Limit to one extended-release capsule daily
- Discontinue when tolerance to anorectic effect develops; do not exceed max dose
- Prescribe/dispense least amount feasible
Available strengths
- ER cap 105 mg
- tab 35 mg
Contraindications
- History of cardiovascular disease (CAD, stroke, arrhythmias, CHF, uncontrolled hypertension, pulmonary hypertension)
- During or within 14 days after MAOIs
- Hyperthyroidism
- Glaucoma
- Agitated states
- History of drug abuse
- Pregnancy
- Nursing
- Combination with other anorectic agents or CNS stimulants
- Known hypersensitivity or idiosyncratic reactions to sympathomimetics
Cautions
- Do not combine with other anorectic agents (incl. OTC/herbal)
- Primary pulmonary hypertension (23-fold risk with >3 months use)
- Valvular heart disease; not recommended with heart murmur/valvular disease
- Tolerance within a few weeks — discontinue
- Hypertensive crisis with MAOIs (within 14 days)
- Abrupt cessation after high dose: extreme fatigue, depression
- Impaired ability to drive/operate machinery
- Not recommended if any anorectic used within prior year
- Caution in mild hypertension; insulin/hypoglycemic needs may change
- Schedule III; abuse/dependence potential
Adverse reactions
- Palpitation, tachycardia, elevated BP, ischemic events
- Primary pulmonary hypertension / valvular disease
- Overstimulation, restlessness, insomnia, agitation
- Flushing, tremor, sweating
- Dizziness, headache, blurred vision
- Psychotic state
- Dry mouth, nausea, stomach pain
- Diarrhea, constipation
- Urinary frequency, dysuria, changes in libido
Pregnancy Contraindicated — weight loss offers no benefit in pregnancy and may cause fetal harm
Lactation Contraindicated (nursing); unknown if excreted in milk, amphetamines are — discontinue nursing or drug
Cost
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 105 mg | ER cap | 60 BID | $202.92 | not offered |
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Self-check
- Phendimetrazine: Which active stimulant is produced from it?
Phenmetrazine. - Phendimetrazine: Which enzyme-inhibitor class should be avoided?
MAOIs.